Q&A: Intermittently stopping

Geoff's 2001 Holden Vectra randomly stops when he hits bumps in the road.

Q&A: Intermittently stopping

15 August 2014

Question

I have a strange problem with my 2001 2.2-litre petrol Holden Vectra Hatchback, as it intermittently stops. The ignition light stays on and it starts straight away. It actually appears to stop when we hit a bump, which suggests a bad connection in the wiring but tapping, pulling etc produces nothing definitive.

The computer says it has a Cam Sensor Fault, however changing that only made it worse, so I changed back to the original. I also had another look with another computer (different dealer) which showed no data coming from the Mass Air Flow Meter and Sensor. However, this would bring the engine management light on but I don’t think it would stop it suddenly as it does. To be honest, it feels like the fuel is being cut off, but not sure what signals would do that.

Answer

As you are well aware, a problem like this can be extremely hard to diagnose. If the car does stall intermittently when hitting a bump, it could well be a connection problem in the wiring, an earthing issue or even a faulty battery. The ignition, fuel pump and engine relays would also be worth checking for an intermittent connection failure. The problem may not be under the bonnet but at the fuel pump wiring or the pump itself. If the timing belt has travelled more than 60,000kms and the car feels sluggish, the timing may be out due to a cam jumping a tooth on a worn belt also causing codes. Cam, crankshaft sensors and airflow meters are all common faults on Vectra’s and will all cause the engine cutting out. Another possibility; Vectra’s are known to have issues due to carbon build up the cylinder heads and so does the throttle bodies. The idle air control valve also gets affected by carbon and can cause stalling. When new, Holden had a service rework for these engines where extra filtration was fitted to the engine’s breather system to help reduce carbon deposits entering the throttle body. We suggest having a good auto electrician take a look.